Sofugan is a steep-sided pinnacle that rises 99 m above the sea surface south of Torishima volcano. Its dramatic and isolated setting prompted it to also be known as "Lot's Wife Rocks." The basaltic-to-andesitic pinnacle is the remnant of a large stratovolcano that is 28 km wide at its base and rises 2200 m above the sea floor. A submarine depression lies between the pinnacle and an arcuate submarine ridge to the SW that rises to less than 150 m of the sea surface. In 1975 discolored sea water was observed about 500 m north of Sofugan, and the volcano was reclassified as active by the Japan Meteorological Agency in 2003.